This invention relates to a new greasing device, and in particular, it relates to a device used for lubricating or greasing. The invention comprises a high efficiency grease gun that adopts a sealed grease barrel grease-self-absorption technique.
Greasing devices commonly are used to lubricate the frictional parts of machines with oil or grease. A simple grease gun device is mainly composed of a grease applying device and a grease storage device, for example, the typical grease gun device used to apply semi-solid grease. The grease applying device consists of a cock body, a greasing piston, a pressure rod, a unidirectional locking ball, and a pressure spring. When the pressure rod is pushed down, it drives the greasing piston to push the lubricating grease through the locking ball to the flow nipple, through which the grease is applied to the frictional parts of the machine. The unidirectional locking ball and the pressure spring are fixed inside the grease groove to form a one-way valve so that the grease is moved forward and not sent back to the cylinder.
The grease storage device is a grease storage barrel, in which a piston and a piston rod are located. An energy-storage spring is fixed on the external side of the piston, and when pressure is exerted on the piston surface, grease inside the grease barrel will be pushed into the cylinder of the grease applying device. When the pressure rod is lifted after one action of greasing is finished, a negative pressure is formed inside the cylinder, and the pressure of the energy-storage spring drives the grease inside the grease barrel quickly into the cylinder to prepare for a second greasing process when pressure is again exerted on the pressure rod.
However, it is very inconvenient to fill the above-mentioned grease gun with grease. After the grease-storage barrel is dismantled from the cock body, the piston pull rod is drawn to enable the grease barrel piston to return to the bottom of the grease barrel so that additional grease can be placed in the grease barrel. After the piston rod returns to the bottom of the grease barrel, the pull rod is fixed onto the rear cover by a safety groove on the rod. When the rod is pulled, the energy-storage pressure spring will exert a great pressure onto the piston. At this moment, the safety unit is likely to break away because of vibrations, and the piston may spring back abruptly, at which time grease in the grease barrel may be ejected out, resulting in wasted grease. Moreover, this kind of grease filling method is likely to result in impurities, such as sand or short fibers, being filled into the grease storage barrel, and these impurities might block up the grease nipple of the greasing device. Furthermore, the grease barrel piston tightness in this kind of structure is not very good, and grease may easily leak from the rod or piston wall. The leakage of grease is not only a waste, but it will pollute the task environment as well.
Although the above-described greasing device has its defects, it is still widely used today because its structure is simple and alternative products do not exist.
The aim of this invention is to design a new greasing device, and particularly a high efficiency grease gun. This tool overcomes the shortcomings of traditional products. Moreover, it is easy to fill this tool with grease. Grease barrel tightness is good so that grease leakage is effectively prevented; and therefore, this tool not only raises the grease utilization ratio, but it also makes the operation process clean.
In accomplishing the above aims, this invention greatly improves the structure of the traditional grease applying device. It not only retains the favorable characteristics of traditional greasing devices, such as having a simple structure and being flexible in operation, but it also changes the structure of the grease storage part from that of traditional products. The device according to the invention is easy to fill with grease, and the tightness of the grease storage barrel is good so that the grease utilization ratio and the grease filling quality are improved.
Specifically, the high efficiency grease gun in accordance with this invention consists of two parts: a grease applying device and a grease storage device. These parts have the characteristics described below.
The grease storage device consists of a sealed grease barrel and a jacket. The sealed grease barrel is a barrel-type device with an opening at one end. Inside the barrel is a sealed piston. The sealed grease barrel is mounted on a cock body of the greasing device piston. The opening of the sealed grease barrel leads to the grease slot of the cock body, and the grease barrel is sealed properly so that grease in the sea ed grease barrel can enter into the greasing cylinder through the barrel opening and the grease slot. A simple installation method includes mounting and fixing the sealed grease barrel on the cock body with the joint sealed using the screw threads on the barrel opening and on the grease slot of the cock body.
Another feature of the grease storage device according to this invention is that an energy-storage spring is not employed. However, because the grease gun is a frequently-used tool, in order to make its use convenient and to provide a prolonged life for the grease gun, a jacket is mounted on the external side of the sealed grease barrel, and the jacket is fixed on the cock body of the greasing device. Inside the jacket, an energy-storage spring is not used to push the sealed piston in the sealed grease barrel.
The greasing device is made up of a cock body, a grease filler plug, a cylinder, a pressure spring, a locking ball, and a seal washer. A slot is cut on the internal wall of the cylinder, and the seal washer is located on the slot. The sealed slot is located on the external cavity of the cylinder, and it improves the tightness between the cylinder wall and the greasing piston so that when the greasing piston operates, grease leakage between the cylinder wall and the greasing piston can be prevented. The seal washer can be made of oil resistant rubber and resin which has good oil resistance.
The principles of this invention are different from those of well-known greasing devices. Because there is no energy-storage spring in the jacket of the grease gun, grease in the sealed grease barrel is not pushed into the cylinder cavity by a spring force exerted on the sealed piston. Rather, grease is drawn into the cylinder cavity by the negative pressure inside the cylinder cavity. When the pressure rod is compressed and then lifted, the good tightness between the greasing piston and the cylinder wall caused by the seal washer makes it possible for a negative pressure to exist inside the cylinder cavity, and atmospheric pressure moves the sealed piston in the sealed grease barrel forward to draw grease from the grease barrel to fill in the cylinder cavity.
In conventional greasing devices, there is no sepal washer, and therefore, the tightness between the greasing piston and the cylinder wall is not good enough to form a sufficient negative pressure when the greasing piston moves outward. Accordingly, the pressure of the energy-storage spring has to be used to push grease into the cylinder cavity.
Moreover, in the device according to the invention, there is only a sealed grease barrel inside the grease gun, and there is no piston rod. Not only is the structure greatly simplified, but also the grease leakage problem, which is usually caused by bad tightness between the piston and rod, is solved. Grease filling is carried out without any elastic force, so it is very easy to fill the sealed grease barrel with grease, thus avoiding the undesirable event described above that often occurs when filling the grease storage barrel with grease. The device according to the invention is convenient to fill with grease, and the possibilities of mixing impurities in with the grease are greatly reduced. The sealed grease barrel, as used in this invention, can be made of plastics or sheet metal, and because of their low cost, disposable sealed grease barrels can be manufactured. Dedicated devices can be used to fill grease into the sealed grease barrel to effectively guarantee grease quality. In use, the cap of the sealed grease barrel is removed before use, the grease barrel is fixed on the cock body, and, in this manner, the grease filling process is conducted. Compared with traditional grease gun products, the grease gun according to the invention is flexible and convenient to use.
In order to further improve the above-mentioned device, the manufacturing engineering of the product has been improved, and the working accuracy of the cylinder and the greasing piston in the greasing device has been increased to ensure that the movable fit clearance between the cylinder and the greasing piston is less than 60 .mu.m. This not only increases the tightness of the cylinder and the greasing piston, but it also effectively prevents grease from returning to the sealed grease barrel along the clearance between the cylinder and the greasing piston during the process of filling the cylinder with grease. Fit clearance between the cylinder and the greasing piston in traditional grease guns is comparatively large, and a considerable amount of grease returns to the grease barrel during the process of filling the cylinder with grease so that the operating efficiency of the greasing device is decreased. The greasing efficiency of this invention is increased more than 30% as compared with ordinary greasing devices.